Cadia, a steadfast bulwark against Chaos for ten thousand years, has fallen. The downfall of the planet brought about by Abaddon and the Thirteenth Black Crusade has broken the empire of mankind. A conflagration of heresy, lies, and insurrection is spreading. It is now up to the battered but unyielding survivors of Cadia to continue the fight in the Emperor's name.
On the plane of Malouri, traitor forces have retreated to the island fortress of Crannog Mons. After a years-long stalemate, Minka Lesk and the 101st Cadia Regiment are tasked with breaking the siege. Amidst the bloody and costly carnage they find themselves in, they must find the answer to one question: in a galaxy where Cadia no longer exists, what does it mean to still be Cadians?